Display apparatus and display unit

ABSTRACT

A display apparatus includes a display unit projecting an image to a light transmissive display member, and the display apparatus forms a virtual image of the image projected by the display unit on an opposite side to a user side. The display unit is configured to accommodate a display device displaying the image and a projection optical system that projects the image displayed on the display device to the display member in a housing. The projection optical system includes a first reflecting member disposed on a display device side and a second reflecting member disposed on an opening side in an optical path extending from the display device. A reflection surface of the first reflecting member reflecting the image displayed on the display device has a convex shape, and a reflection surface of the second reflecting member projecting the image to the display member has a concave shape.

BACKGROUND

1. Technical Field

The present technology relates to a display apparatus that enables avirtual image of a display image to be visually perceived by projectingthe display image to a light transmissive display member.

2. Description of Related Art

Unexamined Japanese Patent Publication No. 2013-25205 discloses a headupdisplay including a curved screen that corrects a field curvature of avirtual image. Unexamined Japanese Patent Publication No. 2013-111999discloses a headup display that divides a display image into two screensand displays the display image.

SUMMARY

A display apparatus according to the present technology includes adisplay unit that projects an image to a light transmissive displaymember, and the display apparatus forms a virtual image of the imageprojected by the display unit on an opposite side to a user side withrespect to the display member. The display unit is configured toaccommodate a display device that displays the image and a projectionoptical system that projects the image displayed on the display deviceto the display member in a housing including an opening through whichprojected light is output. The projection optical system includes afirst reflecting member disposed on a display device side and the secondreflecting member disposed on an opening side in an optical pathextending from the display device to the opening. A reflection surfaceof the first reflecting member that reflects the image displayed on thedisplay device has a convex shape, and a reflection surface of thesecond reflecting member that projects the image to the display memberhas a concave shape of a free-form surface. The first reflecting memberand the second reflecting member are disposed so as to satisfy arelation of 0.2<D12/Lv<1.3. Where Lv is a length in a longitudinaldirection of the virtual image of the image, and D12 is an intervalbetween the first reflecting member and the second reflecting member ina center optical path.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory view illustrating a configuration of anon-vehicle display apparatus provided with a display unit according toan exemplary embodiment of the present technology.

FIG. 2 is a perspective view illustrating a configuration of the displayunit used in the on-vehicle display apparatus.

FIG. 3 is an explanatory view illustrating a schematic configuration ofthe display unit.

FIG. 4 is a plan view illustrating a display surface of a displaydevice.

FIG. 5 is an explanatory view illustrating the case that a displayposition of an image displayed on the display device is changed.

FIG. 6 is an explanatory view illustrating a change of the imageprojected by a projection optical system by changing the displayposition of the image displayed on the display device.

FIG. 7 is an explanatory view illustrating a positional relationshipamong the display device of the display unit, first and second mirrors,a user, and the virtual image.

FIG. 8 is a plan view illustrating a positional relationship of theimage displayed on the display device.

FIG. 9 is an explanatory view illustrating a relationship between an eyebox that is a user's visually recognizable region and a user'srecognizable virtual image in the exemplary embodiment.

FIG. 10 is an explanatory view illustrating a state when the virtualimage is viewed from each of positions (1) to (5) of the eye box that isthe visually recognizable region in the exemplary embodiment.

FIG. 11 is a perspective view illustrating a configuration of a displayunit according to another exemplary embodiment used in the on-vehicledisplay apparatus.

FIG. 12 is a perspective view illustrating another example of the firstmirror.

FIG. 13 is an explanatory view illustrating an example of a mirror inwhich a reflection surface is a free-form surface.

DESCRIPTION OF EMBODIMENT

Hereinafter, a display unit and a display apparatus according to anexemplary embodiment of the present technology will be described withreference to the drawings. However, a detailed description more thannecessary may occasionally be omitted. For example, the detaileddescription of a well-known item and the overlapping description of asubstantially identical configuration may occasionally be omitted. Thisis to avoid the following description from becoming unnecessarilyredundant, and to ease understanding of those skilled in the art. Notethat, the inventor provides the accompanying drawings and the followingdescription in order that those skilled in the art adequately understandthe present technology and does not intend to limit the subject matterdescribed in the claims by the accompanying drawings and the followingdescription.

FIG. 1 is an explanatory view illustrating a configuration of anon-vehicle display apparatus provided with a display unit according toan exemplary embodiment of the present technology.

As illustrated in FIG. 1, in the on-vehicle display apparatus of theexemplary embodiment, display unit 10 that projects an image is disposedin dashboard 21 of vehicle 20. Display unit 10 projects the image towind shield 22 that is a light transmissive display member disposed invehicle 20, thereby forming virtual image 40 of the image projected bydisplay unit 10 on an opposite side to a side of user 30 with respect towind shield 22. User 30 can visually perceive virtual image 40 of theimage projected by display unit 10 through wind shield 22. Centeroptical path L of the projected image is indicated by an alternate longand two short dashes line in FIG. 1, and also in the followingdescription, center optical path L is indicated by the alternate longand two short dashes line in the drawings.

FIG. 2 is a perspective view illustrating a configuration of the displayunit used in the on-vehicle display apparatus. FIG. 2 illustrates thedisplay unit with a housing of the display unit partially cut. FIG. 3 isan explanatory view illustrating a schematic configuration of thedisplay unit.

As illustrated in FIGS. 2 and 3, in display unit 10 of the exemplaryembodiment, display device 12 that displays the image and a projectionoptical system that projects the image displayed on display device 12 towind shield 22 that is the display member are accommodated in housing 11including opening 11A. Therefore, user 30 can visually perceive virtualimage 40 of the image through wind shield 22 of the display member. User30 can visually perceive virtual image 40 of the image projected to windshield 22 of the display member from eye box 31 that is apreviously-assumed visually recognizable region.

Opening 11A of housing 11 constitutes an outgoing port of projectedlight of the projection optical system. In opening 11A of housing 11, alight transmissive cover such as a transparent resin sheet may bedisposed so as to close opening 11A.

For example, a liquid crystal display apparatus, an organic EL displayapparatus, and a plasma display are used as display device 12. Indisplay device 12, a predetermined image is displayed in a displayregion of display device 12 using an image signal input from displaycontroller 15.

The projection optical system includes first mirror 13 and second mirror14 in an optical path from display device 12 to wind shield 22 of thedisplay member. First mirror 13 is a first reflecting member disposed onthe side of display device 12. Second mirror 14 is a second reflectingmember disposed on the display member side, namely, on the side ofopening 11A through which the projected light for the image displayed ondisplay device 12 is output.

As illustrated in FIG. 2, in housing 11 of display unit 10, opening 11Athrough which the projected light is output includes first end 11B thatis formed in a rim on the side of first mirror 13 of opening 11A andsecond end 11C that is formed in a rim on the side of second mirror 14of opening 11A. Display device 12 is disposed such that the displayregion where the image is displayed is located on the side of firstmirror 13 with respect to straight line LS connecting first end 11B andsecond end 11C. Therefore, even if the light is incident on display unit10, the incidence of the light on the display region of display device12 can be restrained to form high-quality virtual image 40.

FIG. 4 is a plan view illustrating a display surface of the displaydevice. As illustrated in FIG. 4, rectangular display device 12 includesrectangular display region 12A where predetermined image 16 is displayedusing the image signal input from display controller 15 and non-displayregion 12B that is formed around display region 12A. Image 16 displayedon display device 12 becomes a vertically- and horizontally-reversedimage with respect to virtual image 40 displayed by display unit 10.Marks (1), (2), (3), and (4) indicating positions of virtual image 40 inFIG. 3 and marks (1), (2), (3), and (4) indicating positions of image 16in FIG. 4 show that image 16 displayed on display device 12 becomes theinverted image with respect to virtual image 40 formed by display unit10.

Display controller 15 controls the image signal input to display device12, which enables the display positions of image 16 to be changed indisplay region 12A.

FIG. 5 is an explanatory view illustrating the case that the displayposition of the image displayed on the display device is changed. FIG. 6is an explanatory view illustrating a change of the image projected bythe projection optical system by changing the display position of theimage displayed on the display device.

As illustrated in FIG. 5, display controller 15 controls the imagesignal, which enables the image displayed on display device 12 to bechanged from display position 16A to display position 16B. Note that,display positions 16A and 16B are not limited to the two places, butdisplay controller 15 can set display positions 16A and 16B to arbitrarypositions.

As illustrated in FIG. 6, when display position 16A of the image iscontrolled so as to be changed to display position 16B, the centeroptical path of the projected image is changed from L1 to L2, therebychanging the position of a viewpoint of user 30 who visually perceivesvirtual image 40.

That is, in display unit 10 of the exemplary embodiment, the positionwhere the image is displayed on display device 12 can be changed bycontrolling display controller 15, and user 30 can visually perceiveproper virtual image 40 according to the position of the viewpoint ofuser 30. For example, an attachment error of display unit 10 isgenerated when display unit 10 is installed on vehicle 20. In displayunit 10 of the exemplary embodiment, when display controller 15 iscontrolled to adjust the display position of the image displayed ondisplay device 12, user 30 can visually perceive proper virtual image40. Therefore, the attachment error can be corrected in display unit 10itself. Sometimes the position of the viewpoint of user 30 changes whenthe position of user 30 changes. In such cases, display controller 15 iscontrolled to adjust display positions 16A and 16B of image 16 displayedon display device 12, which allows user 30 to visually perceive propervirtual image 40.

In the display apparatus of the exemplary embodiment, desirably theviewpoint of user 30 is located in a substantial center of eye box 31that is the visually recognizable region in order that user 30 canvisually perceive proper virtual image 40. Accordingly, in the case thatthe position of the viewpoint of user 30 changes, display controller 15controls the display positions 16A and 16B of image 16 displayed ondisplay device 12 to be moved such that the viewpoint of user 30 islocated in the substantial center of eye box 31 that is the visuallyrecognizable region.

According to an experimental result, desirably Vi/Is is greater than orequal to 2 and less than 7. Where Vi is a movement amount of the user'sviewpoint region and Is is a movement amount of image 16 displayed ondisplay device 12. More desirably, display controller 15 controls themovement amount of image 16 such that Vi/Is is greater than or equal to4 and less than 6. The experimental result showed that a distortion ofthe image observed in eye box 31 of user 30 increases when Vi/Is isgreater than or equal to 7, and eye box 31 that is the visuallyrecognizable region of user 30 is narrowed when Vi/Is is less than 2.

First mirror 13 that is the first reflecting member of the projectionoptical system is disposed above a display surface of display device 12,namely, immediately above display region 12A. In first mirror 13,reflection surface 13A that reflects the image displayed on displaydevice 12 has a convex shape of a free-form surface. Second mirror 14that is the second reflecting member of the projection optical system isdisposed immediately below wind shield 22 that is the display member onthe optical path on which the image is reflected by reflection surface13A of first mirror 13. In second mirror 14, reflection surface 14A thatfaces reflection surface 13A of first mirror 13 and projects the imageto wind shield 22 that is the display member has a concave shape of thefree-form surface.

The arrangements of display device 12, first mirror 13, and secondmirror 14 in display unit 10 will be described below.

FIG. 7 is an explanatory view illustrating a positional relationshipamong the display device of the display unit, the first and secondmirrors, the user, and the virtual image. FIG. 8 is a plan viewillustrating a positional relationship of the image displayed on thedisplay device. Each symbol illustrated in FIGS. 7 and 8 is defined asfollows. An interval between display device 12 and first mirror 13 andan interval between first mirror 13 and second mirror 14 mean a lengthof the center optical path.

D12: Interval between first mirror 13 and second mirror 14 in centeroptical pathLv: Length (T×tan θ) in longitudinal direction of virtual image 40T: Distance from pupil of user 30 to virtual image 40 in center opticalpathθ: Angle in a vertical direction when virtual image 40 is viewed frompupil of user 30Yv: Length (corresponding to length in perpendicular direction ofvirtual image) in longitudinal direction of image 16 displayed ondisplay device 12DL1: Interval between first mirror 13 and image 16 of display device 12

In the display apparatus provided with display unit 10 of the exemplaryembodiment, first mirror 13 and second mirror 14 are disposed such thatinterval D12 between first mirror 13 and second mirror 14 satisfies0.2<D12/Lv<1.3. Desirably, first mirror 13 and second mirror 14 aredisposed such that interval D12 between first mirror 13 and secondmirror 14 satisfies 0.5<D12/Lv<1.0. More desirably, first mirror 13 andsecond mirror 14 are disposed such that an upper limit of interval D12between first mirror 13 and second mirror 14 satisfies D12/Lv<0.9.

Therefore, user 30 can visually perceive sufficiently large virtualimage 40 in small-size display unit 10 having the small interval betweenfirst mirror 13 and second mirror 14. An increase in curvature of secondmirror 14 can be restrained, and a screen distortion of virtual image 40can easily be corrected. That is, in the exemplary embodiment,downsizing of display unit 10 can be provided.

In the display apparatus of the exemplary embodiment, a relationshipbetween length Yv in the longitudinal direction of image 16 displayed ondisplay device 12 and distance T in the center optical path from user 30to virtual image 40 satisfies 0.03<√(T×Lv)/Yv<0.22.

In the exemplary embodiment, when the relationship of √(T×Lv)/Yv betweenlength Yv in the longitudinal direction of image 16 and distance T fromuser 30 to virtual image 40 is larger than 0.22, the distance from user30 to virtual image 40 increases to enlarge the display apparatus. Onthe other hand, when the relationship of √(T×Lv)/Yv between length Yv inthe longitudinal direction of image 16 and distance T from user 30 tovirtual image 40 is smaller than 0.03, it is necessary to increase thelength in the longitudinal direction of image 16 displayed on displaydevice 12, which results in the enlarged display unit 10. That is, inthe exemplary embodiment, the downsizing of display unit 10 can beprovided, and the downsizing of the display apparatus provided withdisplay unit 10 can be provided.

In the display apparatus provided with display unit 10 of the exemplaryembodiment, interval D12 between first mirror 13 and second mirror 14and interval DL1 between first mirror 13 and image 16 of display device12 satisfy 3.0<D12/DL1. Desirably interval D12 between first mirror 13and second mirror 14 and interval DL1 between first mirror 13 and image16 of display device 12 satisfy 3.5<D12/DL1<10.0. More desirablyinterval D12 between first mirror 13 and second mirror 14 and intervalDL1 between first mirror 13 and image 16 of display device 12 satisfy5.0<D12/DL1<8.0.

In the exemplary embodiment, when interval D12 between first mirror 13and second mirror 14 and interval DL1 between first mirror 13 and image16 of display device 12 satisfy 3.0<D12/DL1, the increase in curvatureof second mirror 14 can be restrained, and the screen distortion ofvirtual image 40 can easily be corrected. That is, in the exemplaryembodiment, downsizing of display unit 10 can be provided.

FIG. 9 is an explanatory view illustrating a relationship between theeye box that is the user's visually recognizable region and the user'srecognizable virtual image in the exemplary embodiment. In FIG. 9,virtual image 40 is viewed from lower left position (3) of eye box 31.FIG. 10 is an explanatory view illustrating a state when the virtualimage is viewed from each of positions (1) to (5) of the eye box that isthe visually recognizable region in the exemplary embodiment. As usedherein, the visually recognizable region (eye box) means a region wherethe user can observe the whole virtual image without omission. In theexemplary embodiment, the visually recognizable region has a rectangularshape of 120 mm×35 mm.

As illustrated in FIG. 10, in the display apparatus of the exemplaryembodiment, the screen distortion is corrected in the whole region ofeye box 31 when virtual image 40 is viewed from positions (1) to (5) ofeye box 31. That is, user 30 can visually perceive good virtual image 40in the whole region of eye box 31.

FIG. 11 is a perspective view illustrating a configuration of a displayunit according to another exemplary embodiment used in the on-vehicledisplay apparatus. In housing 11 of display unit 10 of another exemplaryembodiment, as illustrated in FIG. 11, first light shielding section 11Dis provided at a rim on the side of first mirror 13 of opening 11Athrough which the projected light passes, and second light shieldingsection 11E having a shape cut and raised from housing 11 is provided ata rim on the side of second mirror 14 of opening 11A. First lightshielding section 11D includes first end 11B, and second light shieldingsection 11E includes second end 11C. Display device 12 is disposed suchthat the display region where the image is displayed is located on theside of first mirror 13 with respect to straight line LS connectingfirst end 11B and second end 11C.

Therefore, even if the light is incident on display unit 10, theincidence of the light on the display region of display device 12 can berestrained to form high-quality virtual image 40. Additionally, inanother exemplary embodiment, display unit 10 includes first lightshielding section 11D and second light shielding section 11E to enlargean opening area of opening 11A, so that a degree of freedom can beensured in design.

As described above, in the present technology, display unit 10 thatprojects the image is configured to accommodate display device 12 thatdisplays the image and the projection optical system that projects theimage displayed on display device 12 to the display member in housing 11including opening 11A through which projected light is output. Theprojection optical system includes first mirror 13 disposed on the sideof display device 12 and second mirror 14 disposed on the side ofopening 11A in the optical path from display device 12 to opening 11A.Reflection surface 13A of first mirror 13 that reflects the imagedisplayed on display device 12 has the convex shape of the free-formsurface, and reflection surface 14A of second mirror 14 that projectsthe image to the display member has the concave shape of the free-formsurface. First mirror 13 and second mirror 14 are disposed so as tosatisfy 0.2<D12/Lv<1.3. Where Lv is the length in the longitudinaldirection of virtual image 40, and D12 is the interval between firstmirror 13 and second mirror 14 in the center optical path.

Therefore, user 30 can visually perceive sufficiently large virtualimage 40 in small-size display unit 10 having the small interval betweenfirst mirror 13 and second mirror 14. An increase in curvature of thesecond mirror 14 can be restrained, and a screen distortion of virtualimage 40 can easily be corrected. That is, in the exemplary embodiment,downsizing of display unit 10 can be provided.

In the present technology, the screen distortion generated in windshield 22 that is the display member having the predetermined curvaturecan be corrected well. Therefore, the screen distortion is decreased inthe virtual image of the image formed on the opposite side to the userside of the display member, and the user can visually perceive thevirtual image without sensing an uncomfortable feeling.

In display unit 10 of the present technology, desirably reflectionsurface 13A of first mirror 13 has a rotationally asymmetric convexshape. Therefore, the screen distortion can be corrected well over thewhole user's viewpoint region. Desirably reflection surface 13A of firstmirror 13 has the convex shape in the horizontal direction. Therefore,the curvature in the horizontal direction of reflection surface 14A ofsecond mirror 14 can be increased and the display apparatus can bedownsized.

In the exemplary embodiment, by way of example, reflection surface 13Aof first mirror 13 has the convex shape of the free-form surface.Alternatively, reflection surface 13A may be formed by a toroidalsurface having a convex shape in the horizontal direction. As usedherein, the toroidal surface means an aspherical shape in which thehorizontal direction differs from the perpendicular direction orthogonalto the horizontal direction in the curvature.

Rotationally asymmetric reflection surface 13A of first mirror 13 mayhave a shape in which the X-axis direction differs from the Y-axisdirection in the curvature as illustrated in FIG. 12.

FIG. 13 is an explanatory view illustrating an example of the mirror inwhich the reflection surface is the free-form surface. As illustrated inFIG. 13, the reflection surface which is the free-form surface isdefined as follows.

Assuming that reference longitudinal curve F1 and reference crosswisecurve F2 pass through optical axis C of the center optical path of theimage, reflection surface F has reflecting regions θ1, θ2, θ3, and θ4having different curvatures with a point at which reference longitudinalcurve F1 intersects reference crosswise curve F2 as a boundary.

EXAMPLES

Specific examples of the display apparatus of the present technologywill be described below. In Examples described below, the length inTables has a unit (mm), and the angle has a unit (degree). The free-formsurface is defined by the following mathematical formula.

$\begin{matrix}{{\frac{{cr}^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right)c^{2}r^{2}}}} + {\sum\limits_{j = 2}{C_{j}x^{m}y^{n}}}}{j = {\frac{\left( {m + n} \right)^{2} + m + {3n}}{2} + 1}}} & \left\lbrack {{Mathematical}\mspace{14mu} {formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Where z is a sag amount at a position (x,y) from an axis defining thesurface, r is a curvature radius at an origin of the axis defining thesurface, c is a curvature at the origin of the axis defining thesurface, k is a conic constant, and Cj is a coefficient of a monomialx^(m)y^(n).

In each Example, a coordinate origin that is a reference is located inthe center of the image (display surface) displayed on display device12. In Tables, the crosswise direction of the display surface is set toan X-axis, the longitudinal direction is set to a Y-axis, and adirection perpendicular to the display surface is set to a Z-axis.

In Tables, a surface number 1 indicates the display surface of displaydevice 12, a surface number 2 indicates first mirror 13, a surfacenumber 3 indicates the second mirror, a surface number 4 indicates windshield 22, and a surface number 5 indicates the user's viewpoint. Ineccentric data, ADE means a rotation amount of the mirror from theZ-axis direction toward the Y-axis direction about the X-axis, BDE meansa rotation amount of the mirror from the X-axis direction toward theZ-axis direction about the Y-axis, and CDE means a rotation amount ofthe mirror from the X-axis direction toward the Y-axis direction aboutthe Z-axis.

Example 1

TABLE 1 Surface number X-curvature Y-curvature 2 603.2021 2654.4

TABLE 2 Surface number Polynomial coefficient 3 C1  0.00000E+00 C2−3.53809E−02 C3  1.28613E−02 C4  6.92444E−04 C5  5.21278E−06 C6 2.72060E−04 C7 −3.35289E−07 C8 −2.38015E−07 C9 −1.86100E−07 C10−1.06353E−06 C11  2.39274E−09 C12 −1.23325E−10 C13  5.27888E−09 C14−7.12437E−09 C15  1.34163E−08 C16  9.51762E−13 C17 −1.48362E−11 C18 9.29390E−12 C19  4.87235E−12 C20 −1.22754E−10 C21  3.76537E−10 C22−2.41643E−14 C23  5.70609E−14 C24 −1.55312E−13 C25  5.63778E−13 C26−1.72194E−12 C27  3.64513E−12 C28 −6.10356E−12 C29  0.00000E+00 C30 0.00000E+00 C31  0.00000E+00 C32  0.00000E+00 C33  0.00000E+00 C34 0.00000E+00 C35  0.00000E+00 C36  0.00000E+00 C37  0.00000E+00 C38 0.00000E+00 C39  0.00000E+00 C40  0.00000E+00 C41  0.00000E+00 C42 0.00000E+00 C43  0.00000E+00 C44  0.00000E+00 C45  0.00000E+00 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00300E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00

TABLE 3 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Toroidal −1.836 2.033 48.083 −30.836 2.234 0.577 3 Free-formsurface 1.602 116.142 −7.383 −41.903 2.082 0.995 4 Toroidal 12.044 5.809256.018 43.684 5.817 2.521 5 203.349 −755.414 511.993 109.093 6.642−8.320

Example 2

TABLE 4 Surface number Polynomial coefficient 2 C1  0.00000E+00 C2−2.37943E−02 C3  1.69540E−02 C4  6.95718E−04 C5  2.53616E−05 C6 2.93214E−04 C7 −4.97930E−07 C8 −6.24744E−07 C9 −6.72213E−07 C10−4.12374E−07 C11  1.40407E−09 C12 −3.73506E−10 C13  4.88892E−09 C14−3.10558E−09 C15  8.54164E−09 C16 −8.95059E−13 C17 −1.47160E−11 C18−1.83957E−12 C19  2.41168E−11 C20 −1.90336E−10 C21  2.95788E−10 C22−1.14425E−14 C23  9.02420E−14 C24 −1.18772E−13 C25  2.31335E−13 C26−9.13190E−13 C27  3.19186E−12 C28 −4.36103E−12 C29  0.00000E+00 C30 0.00000E+00 C31  0.00000E+00 C32  0.00000E+00 C33  0.00000E+00 C34 0.00000E+00 C35  0.00000E+00 C36  0.00000E+00 C37  0.00000E+00 C38 0.00000E+00 C39  0.00000E+00 C40  0.00000E+00 C41  0.00000E+00 C42 0.00000E+00 C43  0.00000E+00 C44  0.00000E+00 C45  0.00000E+00 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00 3 C1  0.00000E+00 C2  5.55069E−02 C3  2.88012E−02 C4 1.79659E−04 C5 −2.29361E−05 C6 −4.44075E−04 C7 −2.94434E−06 C8−4.46411E−06 C9 −2.97119E−06 C10  3.34442E−06 C11 −1.18069E−08 C12−2.24904E−08 C13  3.83585E−08 C14 −5.06094E−09 C15  1.15003E−07 C16−4.48742E−11 C17  6.52135E−11 C18 −2.66825E−10 C19 −1.44244E−10 C20−1.13270E−09 C21  5.86354E−10 C22 −7.19280E−13 C23  7.83822E−12 C24 5.78822E−14 C25  3.58110E−12 C26 −9.17880E−12 C27  1.87450E−11 C28−7.35955E−11 C29  9.28492E−15 C30 −1.66169E−14 C31 −3.33447E−14 C32−6.11151E−14 C33 −7.48046E−14 C34  1.58819E−13 C35  6.56811E−13 C36 1.08622E−14 C37  0.00000E+00 C38  0.00000E+00 C39  0.00000E+00 C40 0.00000E+00 C41  0.00000E+00 C42  0.00000E+00 C43  0.00000E+00 C44 0.00000E+00 C45  0.00000E+00 C46  0.00000E+00 C47  0.00000E+00 C48 0.00000E+00 C49  0.00000E+00 C50  0.00000E+00 C51  0.00000E+00 C52 0.00000E+00 C53  0.00000E+00 C54  0.00000E+00 C55  0.00000E+00 C56 0.00000E+00 C57  0.00000E+00 C58  0.00000E+00 C59  0.00000E+00 C60 0.00000E+00 C61  0.00000E+00 C62  0.00000E+00 C63  0.00000E+00 C64 0.00000E+00 C65  0.00000E+00 C66  0.00000E+00

TABLE 5 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Free-form surface −0.377 6.917 47.660 −27.080 0.566 −0.024 3Free-form surface 0.676 119.411 −11.103 −40.435 0.556 0.108 4 Toroidal21.177 17.593 255.181 45.060 6.490 4.825 5 245.397 −728.488 528.44011.0670 9.006 −7.980

Example 3

TABLE 6 Surface number X-curvature Y-curvature 2 711.0349 628.2919

TABLE 7 Surface number Polynomial coefficient 3 C1 −7.74625E+00 C2−1.73760E−02 C3 −3.54173E−02 C4  5.57437E−04 C5  4.91213E−05 C6 2.72918E−04 C7  6.70001E−08 C8 −3.68481E−07 C9 −7.18698E−08 C10−1.97712E−07 C11  1.61710E−09 C12  4.96069E−11 C13  3.19279E−09 C14−2.68371E−09 C15  5.40272E−09 C16 −1.87291E−11 C17 −1.72096E−12 C18−5.14945E−12 C19  2.49212E−11 C20  5.59040E−11 C21  2.13743E−11 C22−1.14501E−15 C23 −2.39542E−14 C24  5.34863E−14 C25  5.49852E−13 C26−3.26715E−13 C27 −9.84776E−13 C28 −9.93883E−13 C29  6.07330E−16 C30−1.17494E−16 C31 −8.05043E−16 C32 −2.62095E−15 C33  1.69253E−15 C34−7.25278E−15 C35 −1.56103E−14 C36 −2.44877E−14 C37  9.30119E−19 C38 1.67547E−18 C39  2.20897E−19 C40 −2.43948E−17 C41 −2.78455E−18 C42−9.89926E−18 C43  2.10560E−17 C44  4.10178E−16 C45  3.85909E−16 C46 1.40656E−20 C47 −1.45731E−22 C48  8.90634E−20 C49  9.38960E−20 C50−2.95915E−19 C51 −4.41647E−20 C52  6.92333E−19 C53  1.81955E−18 C54−1.17293E−18 C55  5.72526E−18 C56 −1.43014E−22 C57 −1.67215E−23 C58−4.39331E−22 C59  5.33256E−22 C60  8.68017E−22 C61 −1.46669E−21 C62 4.57527E−21 C63 −3.00340E−21 C64 −2.54986E−20 C65  1.92867E−21 C66−8.45424E−20

TABLE 8 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Toroidal 2.933 1.054 45.949 −39.465 −1.082 −4.335 3 Free-formsurface 8.680 162.225 18.038 −58.032 0.358 −4.453 4 Toroidal 59.47820.245 245.022 31.889 2.347 1.388 5 168.515 −800.395 336.634 96.0384.685 −6.441

Example 4

TABLE 9 Surface number Polynomial coefficient 2 C1  0.00000E+00 C2−1.88798E−03 C3 −1.16384E−02 C4 −2.20104E−05 C5 −5.60173E−05 C6−8.71798E−05 C7 −1.37429E−06 C8 −2.39788E−06 C9 −4.08949E−06 C10 1.08131E−06 C11 −8.45057E−09 C12  4.32821E−09 C13  2.24025E−08 C14 1.51402E−08 C15 −5.48935E−09 C16 −6.11656E−11 C17 −2.97250E−10 C18−1.38852E−10 C19 −1.28160E−10 C20 −4.88795E−10 C21  4.65021E−11 C22 1.79401E−12 C23  9.52643E−13 C24  1.70778E−12 C25  9.42122E−13 C26 2.23806E−12 C27 −1.08763E−12 C28  4.61590E−12 C29  0.00000E+00 C30 0.00000E+00 C31  0.00000E+00 C32  0.00000E+00 C33  0.00000E+00 C34 0.00000E+00 C35  0.00000E+00 C36  0.00000E+00 C37  0.00000E+00 C38 0.00000E+00 C39  0.00000E+00 C40  0.00000E+00 C41  0.00000E+00 C42 0.00000E+00 C43  0.00000E+00 C44  0.00000E+00 C45  0.00000E+00 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00 3 C1 −4.13454E+00 C2 −1.25103E−02 C3 −3.33999E−02 C4 5.57897E−04 C5  4.81348E−05 C6  2.73964E−04 C7 −9.02684E−08 C8−5.62752E−07 C9 −4.16046E−07 C10 −1.75022E−07 C11  1.75704E−09 C12 3.90988E−10 C13  2.80206E−09 C14 −1.45904E−09 C15  4.27866E−09 C16−1.86021E−11 C17 −6.34215E−13 C18 −1.08581E−11 C19  2.13613E−11 C20 4.26555E−11 C21  3.42848E−11 C22 −2.89755E−14 C23 −2.72475E−14 C24 3.73200E−14 C25  4.71097E−13 C26 −2.32457E−13 C27 −1.07144E−12 C28−7.46368E−13 C29  5.65531E−16 C30 −2.56218E−16 C31 −6.36585E−16 C32−1.97885E−15 C33  1.74136E−15 C34 −7.29656E−15 C35 −1.68610E−14 C36−2.53896E−14 C37  5.30403E−19 C38  1.84207E−18 C39 −9.20942E−19 C40−2.48408E−17 C41  3.64698E−18 C42 −6.26492E−18 C43  1.51546E−17 C44 3.47700E−16 C45  3.67879E−16 C46  1.68651E−20 C47  9.24582E−22 C48 1.00871E−19 C49  8.61703E−20 C50 −2.61479E−19 C51  6.79566E−20 C52 6.59543E−19 C53  1.68901E−18 C54 −9.15230E−19 C55  5.51614E−18 C56−1.19051E−22 C57 −7.26209E−24 C58 −4.55573E−22 C59  3.97866E−22 C60 7.64242E−22 C61 −1.46295E−21 C62  3.58028E−21 C63 −4.69101E−21 C64−2.21322E−20 C65  8.72864E−21 C66 −7.82403E−20

TABLE 10 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Free-form surface −3.139 4.384 51.009 −33.675 5.137 −0.818 3Free-form surface 9.725 159.210 1.656 −50.376 5.155 0.690 4 Toroidal37.961 47.706 253.040 39.594 7.745 −3.307 5 119.229 −754.992 459.930103.782 2.822 −13.350

Example 5

TABLE 11 Surface number Polynomial coefficient 2 C1  0.00000E+00 C2 7.43401E−02 C3  1.26031E−01 C4  6.47921E−04 C5  4.33203E−05 C6−9.13686E−06 C7  2.70405E−06 C8 −2.15690E−05 C9 −1.00719E−05 C10 3.62560E−05 C11 −1.28051E−07 C12 −7.41791E−08 C13  1.95578E−07 C14−8.83249E−07 C15  3.04264E−06 C16 −1.63944E−09 C17  5.02021E−09 C18 3.61341E−09 C19  8.54316E−10 C20 −3.00716E−08 C21  8.57783E−08 C22−2.48786E−11 C23  6.08772E−11 C24 −7.51368E−11 C25  2.77465E−11 C26−5.82084E−11 C27 −3.76834E−10 C28  8.58741E−10 C29  0.00000E+00 C30 0.00000E+00 C31  0.00000E+00 C32  0.00000E+00 C33  0.00000E+00 C34 0.00000E+00 C35  0.00000E+00 C36  0.00000E+00 C37  0.00000E+00 C38 0.00000E+00 C39  0.00000E+00 C40  0.00000E+00 C41  0.00000E+00 C42 0.00000E+00 C43  0.00000E+00 C44  0.00000E+00 C45  0.00000E+00 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00 3 C1  0.00000E+00 C2  7.52284E−02 C3 −3.30535E−02 C4 8.44337E−04 C5  6.09928E−05 C6  4.14469E−04 C7  7.24104E−07 C8−1.80204E−06 C9  3.80002E−07 C10 −6.31093E−07 C11  1.57841E−09 C12−3.45145E−09 C13  7.12120E−09 C14 −4.93262E−09 C15  2.35792E−08 C16−1.54142E−11 C17 −3.73411E−11 C18 −3.24326E−11 C19  1.05313E−10 C20−4.81729E−11 C21  2.49310E−10 C22 −1.70460E−13 C23 −8.10118E−14 C24−2.61025E−13 C25 −2.44547E−13 C26  8.29562E−13 C27 −2.79408E−13 C28 9.61641E−13 C29  0.00000E+00 C30  0.00000E+00 C31  0.00000E+00 C32 0.00000E+00 C33  0.00000E+00 C34  0.00000E+00 C35  0.00000E+00 C36 0.00000E+00 C37  0.00000E+00 C38  0.00000E+00 C39  0.00000E+00 C40 0.00000E+00 C41  0.00000E+00 C42  0.00000E+00 C43  0.00000E+00 C44 0.00000E+00 C45  0.00000E+00 C46  0.00000E+00 C47  0.00000E+00 C48 0.00000E+00 C49  0.00000E+00 C50  0.00000E+00 C51  0.00000E+00 C52 0.00000E+00 C53  0.00000E+00 C54  0.00000E+00 C55  0.00000E+00 C56 0.00000E+00 C57  0.00000E+00 C58  0.00000E+00 C59  0.00000E+00 C60 0.00000E+00 C61  0.00000E+00 C62  0.00000E+00 C63  0.00000E+00 C64 0.00000E+00 C65  0.00000E+00 C66  0.00000E+00

TABLE 12 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Free-form surface 3.163 19.185 38.804 −30.903 −2.266 −3.512 3Free-form surface 6.486 129.959 34.777 −62.496 −0.087 −4.178 4 Toroidal1.181 32.392 161.303 26.936 −5.181 −5.854 5 −168.219 −775.561 126.26085.317 −12.157 8.390

Example 6

TABLE 13 Surface number Polynomial coefficient 2 C1  5.31393E+00 C2 6.14628E−02 C3  4.64893E−01 C4  1.79720E−03 C5  1.12476E−04 C6−4.01159E−04 C7  3.25630E−05 C8  4.60919E−06 C9 −6.03291E−05 C10−3.58176E−05 C11 −3.92909E−07 C12  7.98664E−07 C13  1.72870E−06 C14−5.87419E−06 C15  3.61494E−06 C16 −2.52222E−08 C17 −1.72663E−08 C18 7.33649E−08 C19  4.18832E−08 C20 −1.57336E−07 C21  2.09544E−07 C22−4.57278E−10 C23 −9.57855E−10 C24  2.75575E−10 C25  1.64775E−09 C26 6.44462E−11 C27 −4.46906E−10 C28  2.14478E−09 C29 −3.42160E−12 C30−1.09891E−11 C31 −4.89577E−12 C32 −3.37324E−12 C33  1.53945E−12 C34 1.01476E−11 C35  6.54663E−11 C36 −5.37173E−11 C37 −6.59034E−15 C38−3.14026E−14 C39 −1.17757E−14 C40 −1.12045E−13 C41 −3.18189E−13 C42 1.10232E−13 C43  4.23078E−13 C44  1.00736E−12 C45 −9.14181E−13 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00 3 C1  0.00000E+00 C2  2.08429E−02 C3  1.26733E−01 C4 1.60031E−03 C5 −7.79659E−05 C6  1.12460E−03 C7  9.69798E−07 C8−9.17625E−07 C9  1.62879E−06 C10  3.34641E−07 C11  1.67478E−09 C12 1.62408E−09 C13 −1.95545E−09 C14 −1.00740E−08 C15 −3.43339E−08 C16−8.78711E−12 C17 −2.95545E−11 C18 −1.72777E−10 C19  1.17932E−10 C20 2.38981E−10 C21  1.05279E−09 C22  8.16294E−14 C23 −4.87975E−13 C24−7.68740E−13 C25  3.10216E−13 C26 −1.27347E−12 C27 −3.78998E−12 C28−8.27569E−12 C29  2.09554E−15 C30 −2.43596E−15 C31  2.48185E−15 C32−1.04840E−14 C33  1.81644E−14 C34 −4.60001E−14 C35  6.00041E−15 C36−1.03430E−13 C37  8.17620E−18 C38 −6.90889E−18 C39  4.21005E−18 C40−4.25062E−17 C41  1.97423E−16 C42  2.62493E−17 C43  7.93750E−16 C44 1.57455E−16 C45  1.15341E−15 C46  0.00000E+00 C47  0.00000E+00 C48 0.00000E+00 C49  0.00000E+00 C50  0.00000E+00 C51  0.00000E+00 C52 0.00000E+00 C53  0.00000E+00 C54  0.00000E+00 C55  0.00000E+00 C56 0.00000E+00 C57  0.00000E+00 C58  0.00000E+00 C59  0.00000E+00 C60 0.00000E+00 C61  0.00000E+00 C62  0.00000E+00 C63  0.00000E+00 C64 0.00000E+00 C65  0.00000E+00 C66  0.00000E+00

TABLE 14 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Free-form surface 7.045 22.397 30.974 1.945 −13.108 0.890 3Free-form surface −10.138 67.640 −41.130 −21.652 −12.395 −4.389 4Toroidal −28.813 29.813 232.960 57.727 −10.200 8.929 5 −17.199 −635.508674.614 123.092 0.655 20.204

Example 7

TABLE 15 Surface number X-curvature Y-curvature 2 603.2021 2654.4

TABLE 16 Surface number Polynomial coefficient 3 C1  0.00000E+00 C2−3.53809E−02 C3  1.28613E−02 C4  6.92444E−04 C5  5.21278E−06 C6 2.72060E−04 C7 −3.35289E−07 C8 −2.38015E−07 C9 −1.86100E−07 C10−1.06353E−06 C11  2.39274E−09 C12 −1.23325E−10 C13  5.27888E−09 C14−7.12437E−09 C15  1.34163E−08 C16  9.51762E−13 C17 −1.48362E−11 C18 9.29390E−12 C19  4.87235E−12 C20 −1.22754E−10 C21  3.76537E−10 C22−2.41643E−14 C23  5.70609E−14 C24 −1.55312E−13 C25  5.63778E−13 C26−1.72194E−12 C27  3.64513E−12 C28 −6.10356E−12 C29  0.00000E+00 C30 0.00000E+00 C31  0.00000E+00 C32  0.00000E+00 C33  0.00000E+00 C34 0.00000E+00 C35  0.00000E+00 C36  0.00000E+00 C37  0.00000E+00 C38 0.00000E+00 C39  0.00000E+00 C40  0.00000E+00 C41  0.00000E+00 C42 0.00000E+00 C43  0.00000E+00 C44  0.00000E+00 C45  0.00000E+00 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00

TABLE 17 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Toroidal −1.836 2.033 48.083 −30.835 2.234 0.577 3 Free-formsurface 1.602 116.142 −7.383 −41.903 2.082 0.995 4 Toroidal 12.044 5.809256.018 43.684 5.817 2.521 5 203.349 −755.414 511.993 109.093 6.642−8.320

Example 8

TABLE 18 Surface number Polynomial coefficient 2 C1  0.00000E+00 C2−6.57571E−02 C3 −4.62022E−03 C4  4.20899E−04 C5  3.31024E−04 C6−2.15702E−03 C7  3.14987E−05 C8 −1.70716E−05 C9  1.38602E−05 C10 1.66481E−05 C11  5.55736E−08 C12 −6.23406E−08 C13 −4.48689E−07 C14−8.94241E−07 C15 −6.91527E−07 C16 −2.06883E−08 C17  7.39764E−09 C18−1.73937E−08 C19 −3.35093E−08 C20 −4.47809E−08 C21  3.65465E−08 C22−7.12345E−10 C23 −7.68166E−10 C24  3.18443E−10 C25  1.59290E−09 C26 2.88191E−09 C27  2.36459E−09 C28 −1.48624E−09 C29  1.11929E−11 C30−7.08850E−12 C31  3.58639E−11 C32  3.21771E−11 C33  1.22466E−11 C34 6.76941E−11 C35  9.53552E−11 C36 −8.49188E−11 C37  4.64867E−13 C38 2.62063E−13 C39 −2.32728E−13 C40 −1.72566E−12 C41 −1.30769E−12 C42 1.36316E−13 C43 −3.87410E−12 C44 −5.36870E−12 C45  3.92007E−12 C46 0.00000E+00 C47  0.00000E+00 C48  0.00000E+00 C49  0.00000E+00 C50 0.00000E+00 C51  0.00000E+00 C52  0.00000E+00 C53  0.00000E+00 C54 0.00000E+00 C55  0.00000E+00 C56  0.00000E+00 C57  0.00000E+00 C58 0.00000E+00 C59  0.00000E+00 C60  0.00000E+00 C61  0.00000E+00 C62 0.00000E+00 C63  0.00000E+00 C64  0.00000E+00 C65  0.00000E+00 C66 0.00000E+00 3 C1  0.00000E+00 C2  1.05136E−01 C3 −9.03206E−03 C4 3.19326E−03 C5  3.35742E−05 C6  2.55373E−03 C7  1.46521E−06 C8−1.06354E−06 C9  1.19716E−06 C10 −3.22353E−07 C11  8.49822E−09 C12−1.76954E−09 C13  1.83426E−08 C14  2.01842E−08 C15  4.03481E−08 C16−9.97452E−12 C17 −4.38612E−11 C18  2.75237E−11 C19  7.36894E−11 C20−1.83107E−10 C21 −5.31482E−10 C22 −8.61567E−14 C23 −2.91138E−13 C24−3.14511E−13 C25 −4.12771E−13 C26 −6.36879E−12 C27 −2.56930E−11 C28−3.20213E−11 C29  0.00000E+00 C30  0.00000E+00 C31  0.00000E+00 C32 0.00000E+00 C33  0.00000E+00 C34  0.00000E+00 C35  0.00000E+00 C36 0.00000E+00 C37  0.00000E+00 C38  0.00000E+00 C39  0.00000E+00 C40 0.00000E+00 C41  0.00000E+00 C42  0.00000E+00 C43  0.00000E+00 C44 0.00000E+00 C45  0.00000E+00 C46  0.00000E+00 C47  0.00000E+00 C48 0.00000E+00 C49  0.00000E+00 C50  0.00000E+00 C51  0.00000E+00 C52 0.00000E+00 C53  0.00000E+00 C54  0.00000E+00 C55  0.00000E+00 C56 0.00000E+00 C57  0.00000E+00 C58  0.00000E+00 C59  0.00000E+00 C60 0.00000E+00 C61  0.00000E+00 C62  0.00000E+00 C63  0.00000E+00 C64 0.00000E+00 C65  0.00000E+00 C66  0.00000E+00

TABLE 19 Surface Eccentric data number Shape X Y Z ADE BDE CDE 1 0 0 0 00 0 2 Free-form surface −0.477 4.508 19.660 −36.499 3.118 −0.887 3Free-form surface 5.643 130.971 6.704 −59.994 3.213 0.429 4 Toroidal−101.437 2.506 198.814 30.423 −6.255 −15.582 5 −359.723 −706.261 310.727105.859 −18.828 9.605

Table 20 illustrates examples of the display size of the image, thevirtual image size, and the distance from the user's viewpoint to thevirtual image in Examples 1 to 6. Table 21 illustrates examples ofnumerical values derived from parameters of D12: the interval betweenfirst mirror 13 and second mirror 14, Lv: the longitudinal length (T×tanθ) of virtual image 40, T: the distance from the pupil of user 30 tovirtual image 40 in FIG. 7.

TABLE 20 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6Display size X 97.6 97.6 100.0 100.0 40.9 14.4 Y 36.6 36.6 50.0 50.020.5 38.4 Virtual image size X 420.0 420.0 540.0 540.0 252.0 300.0 Y157.5 157.5 270.0 270.0 126.0 112.5 Distance between pupil and virtualimage 2100 2100 2700 2700 2100 2500

TABLE 21 Exam- Exam- Exam- Exam- Exam- Exam- ple 1 ple 2 ple 3 ple 4 ple5 ple 6 D12/Lv 0.84 0.86 0.61 0.61 0.89 0.90 √(T × Lv)/Yv 0.10 0.10 0.050.05 0.16 0.20

The present technology is suitable for the display apparatus, such asthe on-vehicle headup display, in which the high image quality isrequired.

What is claimed is:
 1. A display apparatus comprising a display unitthat projects an image to a light transmissive display member, thedisplay apparatus forming a virtual image of the image projected bydisplay unit on an opposite side to a user side with respect to thedisplay member, the display unit is configured to accommodate a displaydevice that displays the image and a projection optical system thatprojects the image displayed on the display device to the display memberin a housing including an opening through which projected light isoutput, the projection optical system includes a first reflecting memberdisposed on a display device side and the second reflecting memberdisposed on an opening side in an optical path extending from thedisplay device to the opening, a reflection surface of the firstreflecting member that reflects the image displayed on the displaydevice has a convex shape, a reflection surface of the second reflectingmember that projects the image to the display member has a concave shapeof a free-form surface, and the first reflecting member and the secondreflecting member are disposed so as to satisfy a relation of0.2<D12/Lv<1.3, where Lv is a length in a longitudinal direction of thevirtual image of the image and D12 is an interval between the firstreflecting member and the second reflecting member in a center opticalpath.
 2. The display apparatus according to claim 1, wherein the firstreflecting member and the second reflecting member are disposed so as tosatisfy a relation of 0.5<D12/Lv<1.0.
 3. The display apparatus accordingto claim 1, wherein an interval D12 between the first reflecting memberand the second reflecting member and an interval DL1 between the firstreflecting member and the image of the display device satisfy a relationof 3.0<D12/DL1 in the display apparatus.
 4. The display apparatusaccording to claim 1, wherein a reflection surface of the firstreflecting member has a rotationally asymmetric convex shape.
 5. Adisplay unit that forms a virtual image of an image by projecting theimage to a light transmissive display member, the display unitcomprising: a housing including an opening through which projected lightis output; a display device that is accommodated in the housing anddisplays the image; and a projection optical system that is accommodatedin the housing and projects the image displayed on the display device tothe display member, wherein the projection optical system includes afirst reflecting member disposed on a display device side and a secondreflecting member disposed on an opening side in an optical pathextending from the display device to the opening, a reflection surfaceof the first reflecting member that reflects the image displayed on thedisplay device has a convex shape, a reflection surface of the secondreflecting member that projects the image to the display member has aconcave shape of a free-form surface, and the first reflecting memberand the second reflecting member are disposed so as to satisfy arelation of 0.2<D12/Lv<1.3, where Lv is a length in a longitudinaldirection of the virtual image of the image and D12 is an intervalbetween the first reflecting member and the second reflecting member ina center optical path.
 6. The display unit according to claim 5, whereinthe first reflecting member and the second reflecting member aredisposed so as to satisfy a relation of 0.5<D12/Lv<1.0.
 7. The displayunit according to claim 5, wherein an interval D12 between the firstreflecting member and the second reflecting member and an interval DL1between the first reflecting member and the image of the display devicesatisfy a relation of 3.0<D12/DL1.
 8. The display unit according toclaim 5, wherein a reflection surface of the first reflecting member hasa rotationally asymmetric convex shape.